Review: Rocky Mountain Radar-Laser Detector/Jammers

By Radartest Staff

Original publication date: 4/2003
Last updated: 12/2015

Rocky Mountain Radar invented the "passive" radar jammer. In an attempt to skirt the FCC ban on jammers, these transmit nothing, claiming to defeat a radar gun by adding noise to the signal and reflecting it back to the radar. Not only do some promise to jam both radar and lasers, they're also touted as high-performance detectors.

Curious to see if newer RMR products work better than those of old, we tested some recent models. Here's what we found.

RMR-D312

Dubbed the Mini-D, no doubt because of its small dimensions, the bite-sized RMR-D312 has three buttons atop the case to control all functions. On the left side is the power/volume thumbwheel switch.

RMR-D312

Its list of standard features is brief: city mode, dim/dark mode, manual mute and settings memory. Although claimed are "7-User Selectable Features" and "15 Band Detection", we counted only two selectable features: VG-2 on/off, plus an alternate set of audio tones. The promised 15-band detection (borrowed from Cobra) was also missing.

Other features absent include auto mute, a text display, voice alerts, digital compass, external speaker jack, user-programmable
options and others usually found in detectors in this price range.

Unlike most RMR products, the RMR-D312 doesn't claim to jam radar and laser, just detect them. And according to some of the retailers selling it, the Mini-D is the equal of the Escort Passport 8500 in sensitivity. So we concentrated on examining that claim.

At the Straightaway/Hills Test site the D312 delivered 7,002 feet of range in X-band Highway mode (Escort: 26,916 feet), 221 feet in X-band City mode (Escort: 5,750 feet) and 5,647 feet on K band (Escort: 40,013 feet). By the time it belatedly issued an alert at 3,358 feet on Ka-band (Escort: 40,020 feet) the target vehicle was already well within radar range.

While it was able to sniff out lasers at 3,385 feet (Escort: 5,284 feet), at our standard test-measurement range of 1,000 feet its field of view averaged a paltry 6 inches (Escort: 83 inches). In the real world, the Mini-D's near-blindness to lasers means only a direct hit will set it off, making it useless as a detection device.

After testing this model we were baffled why the company would claim that it bested the Escort Passport 8500 in one of our shootouts.

Eclipse

Apparently positioned as an entry-level model, the Eclipse is a very small package. A trio of top-mounted buttons operates the three-step dim/dark function, manual mute and city/highway controls, respectively.

Signal strength is indicated audibly by beep frequency, visually by three green LEDs. There are separate tones for band identification but like other RMR products, this artless collection of tweets, chirps and whistles is unintelligible even to dedicated bird fanciers. That's why it's especially unfortunate that there's only one LED for both K- and Ka-band ID.

The Eclipse has settings memory and dim/dark but no auto mute, voice alerts, text display or other features generally to be found on models in this price range. And although the box claims it has an X-band delete function, there's no mention of it in the manual and in the days we spent evaluating the Eclipse, no one could find it.

The Eclipse weighed in with decent X-band range and mediocre K- and Ka-band range. The last was so weak that in our difficult Curve Test site, the radar had already locked-in a speed before an alert was sounded.

As a laser detector the Eclipse was a non-starter. It was unable to spot any of the lasers, regardless of range. Considering the performance and features offered by the competition at this price level, we're unable to think of a compelling reason to purchase this detector—although bird-call aficionados might find the audible alerts interesting.

As one of the pricier detectors this model claims to justify the high tariff by promising to "scramble all radar bands (X, K Ka Superwide)" and "scramble ALL laser radar." We'll have to assume that whoever wrote the ad copy is clueless to the fact that there is no similarity between radar and laser. The former uses radio waves and Doppler shift to determine speed, the latter employs amplified light and time-of-flight calculations to achieve the same goal. But no matter, it jams neither.

RMR-C212

The RMR-C212 has four buttons atop the case to control all functions. From the far left are the self-test, dim, manual mute and city/highway switches. On the left side of the case near the front is the power/volume thumbwheel switch.

The C212's case is of translucent plastic, allowing a blurry glimpse inside at its circuit board and waveguide antenna. Unfortunately,
the status and alert LEDs concealed behind the front plastic simply disappear in sunlight, forcing total reliance on the audio alerts to identify threats. Worse, the audio band ID tones, a collection of bird whistles, chirps and tweets, are so indecipherable that we can guarantee that unless you can tune a piano by ear, there's no hope you'll be able to learn what this detector is trying to vocalize.

We might be inclined to overlook some of the RMR-C212's shortcomings if it were a standout performer. Unfortunately, it's critically
deficient in several areas. At the easy Straightaway Test site it delivered adequate X- and K-band detection range but failed to notice the Ka-band radar until some 400 feet after the radar had locked-in our speed.

We also tested the RMR-C212's jamming ability, running it against six different laser models and five types of radar on all three radar bands.

The final score was radar and lasers: 11, Rocky Mountain Radar: 0. The unit had no effect on any of our radar or lasers. Its performance mirrored that of another RMR product we tested, the Black Widow, offered as a laser jammer. (For
a look at what real laser jammers can do, see our most recent laser jammer test.)

In jamming effectiveness the RMR-C212 is on par with the original Spirit jammer, about which we wrote in one magazine story: "You stand a better chance of jamming radar with a box of Kleenex on the dash."

RMR-C302

Somewhat more conventional in appearance than the RMR-C212, this model has a slate-colored plastic housing that sports a trio of buttons across the top for dim, mute and city/highway. A thumbwheel switch on the left side of the case controls power and volume.

Radar and laser band ID are denoted by differently colored LEDs—there is faint lettering etched on each—X, K and Ka, that can be read
when they're lit, although you'll need to hold it up to your eyes to decipher them, and there are three more for signal strength. Like the RMR-C212, this model offers a hopelessly confusing medley of audio alerts which, coupled with its unreadable band ID, makes it a challenge to interpret what information the detector is trying to convey.

Same as the RMR-C212, this model has fewer features than the typical $79 K-Mart Special. We found them to be similar in performance—decent X-band Highway mode and K band range—but there were holes in the performance envelope large enough to drive a Caterpillar D8 dozer through. If you're looking for advance warning of radar traps you'd do better to invest in a pair of prescription eyeglasses.

Like the RMR-C212, this model promises to jam all radar and lasers. And like its stablemate, it does neither. Barring a major rewrite of some of the basic laws of physics, there's no way these devices will ever jam radar or lasers. Priced at $39 we might consider buying one if it were the only detector on the planet, but as a $319 detector/jammer it's hopeless.